/**************背景移动**************/
function Bg(node,speed) {
	this.y;
	this.speed = speed;
	this.node = node;
	
	this.init();
}

Bg.prototype.init=function(){
	this.y = -this.node.clientHeight;
}


Bg.prototype.bgMove = function() {
	this.y += this.speed;
	if(this.y<0){
		this.node.style.transform = `translate3d(0px, ${this.y}px, 0px)`;
	}else{
		this.y = -this.node.clientHeight;
	}
}

/**************背景移动**************/
